org.apache.cassandra.schema

Class DefaultSchemaUpdateHandler

java.lang.Object

org.apache.cassandra.schema.DefaultSchemaUpdateHandler

All Implemented Interfaces:

IEndpointStateChangeSubscriber, SchemaUpdateHandler

public class DefaultSchemaUpdateHandler
extends java.lang.Object
implements SchemaUpdateHandler, IEndpointStateChangeSubscriber

Constructor Summary

Constructors

Constructor and Description
DefaultSchemaUpdateHandler(java.util.function.BiConsumer<SchemaTransformation.SchemaTransformationResult,java.lang.Boolean> updateCallback)
DefaultSchemaUpdateHandler(MigrationCoordinator migrationCoordinator, MessagingService messagingService, boolean requireSchemas, java.util.function.BiConsumer<SchemaTransformation.SchemaTransformationResult,java.lang.Boolean> updateCallback)

Method Summary

Modifier and Type	Method and Description
SchemaTransformation.SchemaTransformationResult	apply(SchemaTransformation transformation, boolean local) Applies schema transformation in the underlying storage and synchronizes with other nodes.
void	beforeChange(InetAddressAndPort endpoint, EndpointState currentState, ApplicationState newStateKey, VersionedValue newValue)
Awaitable	clear() When clear is called the update handler will flag that the clear was requested.
java.util.Map<java.util.UUID,java.util.Set<InetAddressAndPort>>	getOutstandingSchemaVersions()
void	onAlive(InetAddressAndPort endpoint, EndpointState state)
void	onChange(InetAddressAndPort endpoint, ApplicationState state, VersionedValue value)
void	onDead(InetAddressAndPort endpoint, EndpointState state)
void	onJoin(InetAddressAndPort endpoint, EndpointState epState) Use to inform interested parties about the change in the state for specified endpoint
void	onRemove(InetAddressAndPort endpoint)
void	onRestart(InetAddressAndPort endpoint, EndpointState state) Called whenever a node is restarted.
void	reset(boolean local) Resets the schema either by reloading data from the local storage or from the other nodes.
void	start() Starts actively synchronizing schema with the rest of the cluster.
boolean	waitUntilReady(java.time.Duration timeout) Waits until the schema update handler is ready and returns the result.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DefaultSchemaUpdateHandler

public DefaultSchemaUpdateHandler(java.util.function.BiConsumer<SchemaTransformation.SchemaTransformationResult,java.lang.Boolean> updateCallback)

DefaultSchemaUpdateHandler

public DefaultSchemaUpdateHandler(MigrationCoordinator migrationCoordinator,
                                  MessagingService messagingService,
                                  boolean requireSchemas,
                                  java.util.function.BiConsumer<SchemaTransformation.SchemaTransformationResult,java.lang.Boolean> updateCallback)

Method Detail

start

public void start()

Description copied from interface: SchemaUpdateHandler

Starts actively synchronizing schema with the rest of the cluster. It is called in the very beginning of the node startup. It is not expected to block - to await for the startup completion we have another method SchemaUpdateHandler.waitUntilReady(Duration).

Specified by:

start in interface SchemaUpdateHandler

waitUntilReady

public boolean waitUntilReady(java.time.Duration timeout)

Description copied from interface: SchemaUpdateHandler

Waits until the schema update handler is ready and returns the result. If the method returns false it means that readiness could not be achieved within the specified period of time. The method can be used just to check if schema is ready by passing Duration.ZERO as the timeout - in such case it returns immediately.

Specified by:

waitUntilReady in interface SchemaUpdateHandler

Parameters:

timeout - the maximum time to wait for schema readiness

Returns:

whether readiness is achieved

onRemove

public void onRemove(InetAddressAndPort endpoint)

Specified by:

onRemove in interface IEndpointStateChangeSubscriber

onChange

public void onChange(InetAddressAndPort endpoint,
                     ApplicationState state,
                     VersionedValue value)

Specified by:

onChange in interface IEndpointStateChangeSubscriber

onJoin

public void onJoin(InetAddressAndPort endpoint,
                   EndpointState epState)

Description copied from interface: IEndpointStateChangeSubscriber

Use to inform interested parties about the change in the state for specified endpoint

Specified by:

onJoin in interface IEndpointStateChangeSubscriber

Parameters:

endpoint - endpoint for which the state change occurred.

epState - state that actually changed for the above endpoint.

beforeChange

public void beforeChange(InetAddressAndPort endpoint,
                         EndpointState currentState,
                         ApplicationState newStateKey,
                         VersionedValue newValue)

Specified by:

beforeChange in interface IEndpointStateChangeSubscriber

onAlive

public void onAlive(InetAddressAndPort endpoint,
                    EndpointState state)

Specified by:

onAlive in interface IEndpointStateChangeSubscriber

onDead

public void onDead(InetAddressAndPort endpoint,
                   EndpointState state)

Specified by:

onDead in interface IEndpointStateChangeSubscriber

onRestart

public void onRestart(InetAddressAndPort endpoint,
                      EndpointState state)

Description copied from interface: IEndpointStateChangeSubscriber

Called whenever a node is restarted. Note that there is no guarantee when that happens that the node was previously marked down. It will have only if state.isAlive() == false as state is from before the restarted node is marked up.

Specified by:

onRestart in interface IEndpointStateChangeSubscriber

apply

public SchemaTransformation.SchemaTransformationResult apply(SchemaTransformation transformation,
                                                             boolean local)

Description copied from interface: SchemaUpdateHandler

Applies schema transformation in the underlying storage and synchronizes with other nodes.

Specified by:

apply in interface SchemaUpdateHandler

Parameters:

transformation - schema transformation to be performed

local - if true, the caller does not require synchronizing schema with other nodes - in practise local is used only in some tests

Returns:

transformation result

reset

public void reset(boolean local)

Description copied from interface: SchemaUpdateHandler

Resets the schema either by reloading data from the local storage or from the other nodes. Once the schema is refreshed, the callbacks provided in the factory method are executed, and the updated schema version is announced.

Specified by:

reset in interface SchemaUpdateHandler

Parameters:

local - whether we should reset with locally stored schema or fetch the schema from other nodes

clear

public Awaitable clear()

When clear is called the update handler will flag that the clear was requested. It means that migration coordinator will think that we have empty schema version and will apply whatever it receives from other nodes. When a first attempt to apply mutations from other node is called, it will first clear the schema and apply the mutations on a truncated table. The flag is then reset.

This way the clear is postponed until we really fetch any schema we can use as a replacement. Otherwise, nothing will happen. We will simply reset the flag after the timeout and throw exceptions to the caller.

Specified by:

clear in interface SchemaUpdateHandler

Returns:

getOutstandingSchemaVersions

public java.util.Map<java.util.UUID,java.util.Set<InetAddressAndPort>> getOutstandingSchemaVersions()